Protective device for a needle

ABSTRACT

Protective device for a needle, more particularly for a catheter introducing needle or so-called cannula needle, whereby this protective device comprises protective means which slidably cooperate with the needle, characterized in that said protective means comprise a combination of at least, on one hand, safety means having at least one part which, upon retraction of the needle through the protective means, is placed in front of the needle point and prevents the re-use of the needle, and, on the other hand, blocking means which cooperate with the safety means and which, when the protective device passes from a non-operative state into an operative state, release said safety means from a blocked position into an unblocked position.

[0001] This invention is situated within the technical field of medicaland surgical products and relates to a protective device for a needle.

[0002] In first instance, the invention is intended to be used incombination with a catheter introducing needle or cannula needle,however, in general it is not excluded to use it in combination withother types of surgical needles.

[0003] More particularly, the invention relates to a protective devicewhich is capable of avoiding accidental pricking or wounds beinginflicted on health staff during the use of the needles concerned.

[0004] In case of a cannula needle assembly the operator is insertingthe cannula and the needle which is provided in this cannula, byperforating the skin near the patient's vein or artery and introducingthe needle and cannula with their tip into said vein or artery. Once theneedle is inserted, the cannula remains in position, partially withinthe vein, while the needle, which has fulfilled its function, is takenout by the operator.

[0005] This is the phase during which the sharp point of the extractedneedle is dangerously exposed, with a high risk of pricking or woundingthe operator.

[0006] The operation involving replacing the needle into a protectivehood is equally dangerous for the operator replacing it, as numerousspecialised studies have shown statistically.

[0007] In order to avoid this problem and to guarantee the safety ofhealth staff during their activity, various kinds of protection devicesapplicable to cannula needles have been developped.

[0008] Safety cannula needle assemblies are known, having a protectivedevice allowing that the needle can be retracted within a protectiveelement, which may be part of the assembly itself, whereby thewithdrawal is obtained by activating a lever which pushes the needlecorrespondingly into the protective element, or manually, bymanipulating an external handle connected to the needle which can slidealong the axis of the protective element, thereby permitting withdrawalof the needle itself.

[0009] The main disadvantage of these devices, which are already knownto the profession, is the considerable volume of the protective elementwhich may make it laborious and difficult for the operator to use thesecannula needles, resulting in that this known system is less practicaland versatile.

[0010] Another disadvantage of these protective devices, which arealready known to the profession, is not only that they are complicatedor composed of a large number of parts, but also that they entail risksof not working properly and that high production costs are involved inproducing each of the composing parts and in assembling them.

[0011] A further disadvantage is that extra operations are necessarycompared to unprotected devices, entailing the risk of omissions orwrongly executed operations by the operator.

[0012] The profession is also acquainted with protective devices forcannula needles involving the use of a pair of rings linked by aflexible wire. The first ring is fixed to the base of the needle, whilethe second is fixed to the end of the cannula and is intended to guideextraction of the needle and to contain its point. The mechanism makesthe needle slide, during its extraction, through the axial forum of thesecond ring until its further extraction is stopped by the fixed lengthof flexible wire. Hereby, the needle arrives with its needle point intoone of the rings. The needle, fitted into the ring with its pointprotected, can be safely pulled out of the cannula with the entiredevice comprising the two rings and the wire.

[0013] The main disadvantage of this device is the considerableencumbrance entailed by the two protective rings and above all by theflexible wire, which can make it laborious and difficult to use thecannula needle, reducing its functional scope.

[0014] A further disadvantage of these rings and in general of all thedevices known to the profession, is that the patient's body fluids, andsometimes drugs, which may be deposited on the needle as drops or as anadhesive covering, are still accessible and/or that there still is aconsiderable risk that these fluids or drugs leave the protectivedevice. Shocks may cause them to squirt on the bare skin or into theeyes of the operators or of others standing in the proximity thereof,entailing the risk of infection or contamination.

[0015] The main object of this invention is to provide a protectivedevice for needles, more particularly for cannula needles, which allowsto considerably reduce the risk of contact with patient's body fluids orwith drugs on the needle, and which prevents that an accidental prickingand the causing of wounds may happen, all this by means of a devicewhich is compact, resulting in that it is also easy to use and in thatit is very versatile.

[0016] A further aim is to provide a protective device that is easy toconstruct and assemble and hence not expensive.

[0017] Furthermore, this protective device ensures maximum protectionfor the operator during extraction of the needle from the cannula.

[0018] To this end, the invention relates to a protective device for aneedle, more particularly for a catheter introducing needle or so-calledcannula needle, whereby this protective device comprises protectivemeans which slidably cooperate with the needle, which device ischaracterized in that said protective means comprise a combination of atleast, on one hand, safety means having at least one part which, uponretraction of the needle through the protective means, is placed infront of the needle point and prevents the re-use of the needle, and, onthe other hand, blocking means which cooperate with the safety means andwhich, when the protective device passes from a non-operative state intoan operative state, release said safety means from a blocked positioninto an unblocked position.

[0019] The fact that, according to the invention, a combination is madeof safety means with blocking means, which automatically release thesafety means from a blocked into an unblocked position, offers theadvantage that the device functions very efficiently, as will be clearfrom the following detailed description.

[0020] According to a preferred embodiment, the safety means and theblocking means are configured in such a manner that, upon retraction ofthe needle, the safety means, more particularly the part or parts whichare placed in front of the needle point, remain at a distance from theneedle during the entire retraction thereof. In other words, during thecomplete retraction, there is no contact between, on the one hand, thesafety means, more particularly said safety tongue or safety tongues,and, on the other hand, the needle. As a result thereof, the safetymeans, more particularly said tongues, will never urge fluids adhered tothe needle towards the needle point and off the needle point. In thismanner, it is avoided that fluids are scraped completely from the needleand can consequently leave the protective device.

[0021] In the most preferred embodiment, said blocking means areshiftable in respect to the safety means, such that, by means of ashifting movement of the blocking means, the safety means are releasedfrom a blocked position into an unblocked position, whereby saidblocking means cooperate with the needle in such a manner that adisplacement and retraction of the needle also causes the above shiftingmovement of the blocking means. In this way, with a minimum ofconstructive parts, a device is offered which can be actuatedautomatically, just by the retraction of the needle.

[0022] In a practical embodiment, the blocking means substantiallyconsist of a sliding ring located around the needle.

[0023] Preferably, the abovesaid part or parts are elastically bendableand consist of safety tongues, such that these parts are automaticallyurged into the path of the needle upon retraction of the latter. In suchcase, the blocking means can be formed of an element, such as a ring,which in the non-operative state of the protective device, keeps saidparts out of the path of the needle.

[0024] Further, the device is preferably characterized in that theprotective means and the needle comprise stopping means, acting asabutment means between the protective means and the needle, which definean end position when retracting the needle, such that the needle cannotleave the protective means.

[0025] According to a further important preferred feature, theprotective device is provided with scraping means to dry the needle whenthe device itself passes from the non-operative state to the operativestate. These scraping means, which preferably consist of an O-ring,considerably improve the safety of the device, as will become clear fromthe further description.

[0026] Further, it is preferred that said protective means are providedwith a rear wall having a rear side, whereby the scraping means in theiroutermost position remain located at a distance from the rear side ofsaid rear wall. In respect to this, it should be noted that fluids,which are scraped or wiped from the needle, are collected in front ofthe scraping means. At the end, it is never excluded that these fluidsmay penetrate in between the scraping means and the needle surface bymeans of a pumping effect which may be created when moving the needlesidewards in respect to the scraping means. Due to this pumping effect,some fluid may arrive at the rear side of the scraping means. Bypreserving a distance between this rear side and the rear side of therear wall, it is impossible that the operator which handles the devicecan come into contact with the fluid in question.

[0027] It is clear that the fact that the safety tongues do not comeinto contact with the needle during the entire retraction of the needle,is also advantageous in other protective devices for needles. Therefore,according to a second aspect, the invention also relates to a protectivedevice for a needle, more particularly for a catheter introducingneedle, whereby this protective device comprises protective means whichslidably cooperate with the needle, characterized in that saidprotective means comprise one or more safety tongues which uponretraction of the needle are automatically positioned in front of theneedle point, thereby preventing the needle from being re-used, wherebythese tongues upon the complete retraction movement of the needle remainat a distance from the needle.

[0028] Also the abovesaid feature that scraping means, more particularlya scraping ring is used which for all conditions remain at a distancefrom the rear side or the rear wall of the protective device can be usedin combination with other types of protective devices, which must notnecessarily be equipped with blocking means. Therefore, according to athird aspect, the invention also relates to a protective device for aneedle, more particularly for a catheter introducing needle, wherebythis protective device comprises a housing which slidably cooperateswith the needle such that the needle can be retracted upto a position inwhich the needle point is located in said housing, characterized in thatsaid protective device comprises a scraping ring which cooperates withthe needle, whereby this scraping ring is located inside the housing, ata distance from the rear side of the rear wall of said housing.

[0029] It is clear that the invention also relates to needles and safetycannula needle assemblies which are provided with a protective device ofthe invention.

[0030] Other features will become clear from the following detaileddescription and the appended claims.

[0031] In order to better explain the features of the present invention,hereafter, several preferred embodiments are described as exampleswithout being limitative, with reference to the accompanying drawings,in which:

[0032]FIG. 1 represents a cross-section lateral view of a cannula needleassembly provided with a protective device according to the invention,said protective device being in non-operative state;

[0033]FIG. 2 represents an enlargement of the portion which is indicatedby F2 in FIG. 1;

[0034]FIG. 3 represents the portion shown in FIG. 2, during retractionof the needle;

[0035]FIG. 4 represents a cross-section lateral view similar as in FIG.1, however, with the needle in retracted position and with theprotective device being operative;

[0036]FIG. 5 represents an enlargement of the portion which is indicatedby F5 in FIG. 4;

[0037]FIG. 6 represents a cross-section lateral view similar as in FIG.4, however, after that the needle, together with the protective device,is separated from the cannula;

[0038]FIGS. 7 and 8 represent an alternative embodiment of theinvention, for the non-operative and operative state respectively of theprotection device;

[0039]FIGS. 9 and 10 represent a further alternative embodiment of theinvention, for the non-operative and operative state respectively of theprotection device;

[0040]FIGS. 11 and 12 represent a still further alternative embodimentof the invention, for the non-operative state and the state duringretraction of the needle, respectively;

[0041]FIG. 13 represents a perspective view of the part which in FIG. 11is indicated by F13.

[0042] With reference to FIGS. 1 to 6, reference 1 in general indicatesa protective device for a cannula needle 2, which cannula needle 2,together with the cannula 3, forms a complete cannula needle assembly 4.

[0043] With the cannula needle 2, the complete part is meant which isformed by the actual needle 5 and a needle hub 6 in which this needle 5is attached. The needle 5 fits to the cannula 3 and is preferablyhollow. The inner channel 7 is in connection with an opening 8 in theneedle hub 6, which, for example allows a connection with a so-calledflash chamber, or with any other accessory. As represented, the needlehub 6 may be provided with a support 9.

[0044] The cannula 3 is carried out in a conventional manner and mainlyconsists of an elongated hollow front portion 10, which is intended tobe partly introduced in a vein of the patient and which furthermorecomprises a rear portion 11 acting as a cannula hub which is providedwith an entrance opening 12 for introducing the needle 5 into thecannula 3. The entrance opening 12 is also intended to be coupled to atube for fluid supply or the like after retraction of the needle 5. Asshown, the cannula 3 may be provided with one or more additionalentrance openings 13. Of course, the cannula 3 may also be used forintroducing other medical or surgical substances or elements, forexample, for introducing a catheter by means of a vein, artery or thelike into a patient's body.

[0045] The protective device 1 substantially consists of, on the onehand, protective means, generally indicated by reference 14, whichslidably fit onto the needle 5, and, on the other hand, stopping means15, acting as abutment means between the protective means 14 and theneedle 5, which abutment means define an end position when retractingthe needle 5 through the protective means 14.

[0046] Said protective means 14 comprise, on the one hand, safety means16 having at least one part, in this case, a safety tongue 17, which,upon retraction of the needle 5, is placed in front of the point 18 ofthe needle 5, such as to prevent the re-use of this needle and, on theother hand, blocking means 19 which cooperate with the safety means 16and which, when the protective device passes from a non-operative stateA into an operative state B, release said safety means 16 from a blockedposition into an unblocked position, as described in detail in thefollowing.

[0047] As shown, the safety means 16 and the blocking means 19 arepreferably incorporated in a hollow body or housing 20 having a sidewall 21 and two opposed end walls 22-23, which are each provided with apassage opening 24-25 for the needle 5.

[0048] The safety tongue 17 consists of an elastically bendable lip,which in this case forms one part with the end wall 22, and which isconfigured and arranged in such a manner that, in its free position, itextends through the path of the needle 5, preferably in an obliquemanner, as shown in FIGS. 4 to 6.

[0049] The blocking means 19 comprise an element which is shiftablyfitted in the hollow body 20, which element, in the represented example,consists of a ring 26 composed of an inner cylindrical ring part 27 andan outer cylindrical ring part 28 fixedly connected to each other. Theouter cylindrical ring part precisely fits into the hollow body 20.

[0050] The ring 26 is configured such that, in the non-operative state Aof the protection device 1, in which the needle 5 is completely insertedinto the cannula 3, the ring 26 cooperates with the safety tongue 17such that the latter is bent outwardly, in an open position S, in whichthis tongue 17 is not interfering with the needle 5. Hereby, as shown inFIGS. 1 and 2, the tongue 17 and the ring 26, more particularly theouter ring part 28, are slightly hooking behind each other, by means ofa recess 29 in the free end of the tongue 17 and a collar 30 at thefront outer end of said ring part 28.

[0051] The above mentioned stopping means 15 consist of abutment partswhich are provided at the needle 5 and at the protective means 14,respectively. In the embodiment of FIGS. 1 to 6, these abutment partsare formed by an annular groove 31 nearby the point of the needle 5 andretaining means consisting of strips or fins 32 directed towards theaxis of the ring 26 and inclined in the direction opposite to theextraction direction of the needle 5.

[0052] Furthermore, the protective device 1 is provided with scrapingmeans 33 to dry the needle 5 sliding through it, thereby freeing it fromblood or other body fluids from the patient. These scraping means 33consist of a ring, membrane or disk having a central opening, or thelike, fitting with a certain tension around the needle 5, which ring,membrane or disk preferably is made of a flexible synthetic material.More particularly, these means are formed by an O-ring.

[0053] The protective means 14, more particularly the housing 20, iscarried out as an extension piece, which can be coupled to the catheterhub. To this end, the housing is provided with coupling means 34 at theend wall 22, allowing a releasable connection with said catheter hub,preferably by means of a snap connection. To this end, in therepresented embodiment, said coupling means 34 comprise a number ofelastically bendable fins 35, having locking portions 36 which cancooperate with a collar 37 at the rear edge of the rear portion of thecannula 3.

[0054] As shown, the needle hub preferably comprises at least one part38 which, in the most forward position of the needle 5, cooperates withthe protective means 14, thereby preventing the blocking means 14 fromcarrying out a shifting movement from the non-operative position A tothe operative position B. This is obtained in that this part 38 extendsthrough the opening 25 into the hollow body 20, thereby forming anobstacle for the displacement of the blocking means 14. Moreparticularly, as shown in FIG. 2, said shifting is prevented in that thefree end of part 38 comes into contact with said inner ring part 27and/or said fins 35.

[0055] The functioning of the protective device 1 is substantially asdescribed in the following.

[0056] Once the needle 5 and the cannula 3 are inserted into a patient'svein or artery, the needle 5 is retracted from the cannula 3, resultingin that the protective means 14 are automatically activated and are putfrom a non-operative state A into an operative state B.

[0057] In the beginning, in the non-operative state A, the part 38 is incontact with the inner ring part 27, resulting in that the blockingmeans 14 are prevented from being displaced, resulting in that thesafety tongue 17 is kept in the position, as shown in FIGS. 1 and 2.

[0058] When retracting the needle 5, first, this needle freely slidesthrough the protective means 14. From the moment on that the annulargroove 31 arrives at the height of the fins 32, these fins areelastically urged into the annular groove 31, resulting in that theneedle 5 cannot make any further sliding movement through the ring 26.As a consequence, the ring 26 is taken along with the movement of theneedle 5, causing that the ring 26, in other words the blocking means19, are freeing the tongue 17, which interposes itself between thepassage opening 24 and the point 18 of the needle 5, corresponding to astate of release R.

[0059] Upon further retraction, the ring 26 will contact the end wall23, as shown in FIG. 5, and, as a consequence thereof, any furtherextraction movement of the needle 5 from the protective means 14 isprevented. Hereafter, the cannula needle 2 can be disconnected from thecannula 3 by means of the releasable coupling means 34.

[0060] In this way, in the operative state B, the point 18 of the needle5 cannot come out of the protective means 14 because it is blocked, inthe direction of the opening 25 by the activation of the stopping means15, and in the opposite direction by the tongue 17 which is interposedbetween the needle point 18 and the opening 24.

[0061] The protective means 14 are preferably configured in such amanner that any contact between the safety tongue 17 and the needle 5 isexcluded for the complete retraction of the needle 5. In this way, it isexcluded that the safety tongue 17 acts as a scraping element for theneedle 5 and that, on the moment that the tongue 17 is released, bloodor other fluids are projected through the passage opening 24 andpossibly are contaminating this opening. In normal use, in the design ofFIGS. 1 to 6 there will be no contact between the tongue 17 and theneedle point 18 on the moment that the tongue 17 bends back into itsfree position. However, in order to exclude any contact, the point 18can be further shortened, as indicated in dashed line 39 in FIG. 3.

[0062] The geometrical form and the inclination of the fins 32 make itpossible to transfer the needle 5 towards the cannula 3 during the phaseof assembly of the cannula needle assembly 4. Also the blocking means 19are advantageous during the assembly, as by means of these blockingmeans 19, the tongue 17 can be kept in an non-activated state, allowingthe free passage of the needle 5 to the protective means 14.

[0063] During the passage from the non-operative state A to theoperative state B, the needle 5 slides through the scraping means 33which dry it from the liquids that are adhered to this needle 5, therebyretaining these liquids in the hollow body 20. Hence, although the shaftof the needle 5 is no longer sterile, a decisive reduction of anyinfective or toxic products adhered at the needle 5 takes place, therebyreducing the risk for anyone who might have to touch the shaft of theneedle 5 with bare hands. Furthermore, although the hollow body 20 isnot completely closed, the fluids retained in it by the scraping means33 are practically completely held inside, even if the needle 5 were toundergo shocks or vibrations.

[0064] In the embodiment of FIGS. 1 to 6, the coupling means 34 and theend wall 22 are made in one piece and together form a separate Dartwhich acts as a cover which is connected to the side wall 21 in anymanner.

[0065] According to a variant, the coupling means 34 may also be mouldedin a single piece with the hollow body 20.

[0066]FIGS. 7 and 8 show a second embodiment of the protective device 1in which the safety means 16 consist of a pair of opposed elasticallybendable safety tongues 40-41, facing each other and fixed to the endwall 23. The tongues 40-41 have a different length and consist of anelastically bendable first portion 42 which substantially extends inlengthwise direction and, at the distal end of this first portion 42, asecond portion 43 which is directed transversely or substantiallytransversely in respect to the first portion 42. The safety tongues40-41 are configured such that by means of their elasticity, they arepermanently urged towards a position in which the second portions 43 arelocated in the path followed by the needle 5.

[0067] The end wall 23 is carried out in the form of a flange. Thisflange, together with the tongues 40-41 form an insertion piece, which,by means of a snap coupling 44, is mounted into the hollow body 20.

[0068] In this embodiment, the blocking means 19 consist of a ring 45which is located around the needle 5 and in between the tongues 40-41,such that these tongues 40-41 by means of said ring 45 can be kept in anopen state S, as shown in FIG. 7.

[0069] Similarly as in FIGS. 1 to 6, the ring 45 is provided with fins32.

[0070] It should be noted that in FIG. 7 the configuration is chosensuch that the tongues 40-41 are in contact with the ring 45, as well asin contact with the needle 5. Hereby, the tongues 40-41 are only inslight contact with the needle 5, resulting in that, during theretraction of the needle 5, no important frictional forces have to besurmounted.

[0071] It is clear that, according to alternative embodiments anddependent on the diameter of the ring 45 and/or the lengths of thesecond portions 43, there may or may not be a contact between the freeends of the tongues 40-41 and the needle 5.

[0072] In fact, the first aim of the blocking means 19 is to keep thetongues 40-41 separated from each other when no needle 5 is inserted inbetween, thereby allowing that, upon insertion of the needle 5 to theprotective means 14, this needle 5 can be shifted through the hollowbody 20.

[0073] During the passage from the non-operative state A to theoperative state B, the fins 32 engage in the annular groove 31 of theneedle 5 during the latter's axial sliding, thereby causing the ring 45to slide towards the end wall 23. This sliding motion of the ring 45permits the disengaging of the free ends of the tongues 40-41, so as toreach the state of release R, in which these free ends are curvedtowards each other, thus placing the tongues 40-41 between the passageopening 24 and the needle point 18. The different lengths of the tongues40-41 allow the respective free ends to overlap each other, preferablywithout causing any interference, thereby avoiding the possibility ofthe needle 5 coming out of the hollow body 20.

[0074]FIGS. 9 and 10 show a further variant of the invention, the onlydifference with the embodiment of FIGS. 7-8 being that the ring 45 hasno fins 32 and directly fits around the needle 5, whereas the stoppingmeans 15 at the needle 5 consist of a ridge 46 or thickening nearby theneedle point 18. In this way, the side 47 of the ring 45 forms anabutment for the ridge 46.

[0075] An advantage of this embodiment consists in the fact that thescraping means 33 and the abutment means cooperating with the ridge 46are formed by one and the same part, namely said ring 45. Furthermore,this ring 45 also acts as blocking means 19, resulting in that itsimultaneously fulfills three functions.

[0076]FIGS. 11 and 12 relate to a further embodiment. An importantdifference with the embodiment of FIGS. 9 and 10 consists in that thetongues 40-41 and the ring 45 are dimensioned such that in thenon-operative state A of the protective device 1 there is no contactbetween the tongues 40-41 and the needle 5 and furthermore also duringthe entire retraction of the needle 5 no such contact takes place. FIG.12 shows an intermediate position, which demonstrates that the tongues40-41 nicely close around the needle point 18, without touching thelatter. As explained in respect to the embodiment of FIGS. 1 to 6, thisoffers the advantage that the tongues 40-41 are not acting as scrapingelements, resulting in that no drops of blood or other fluids arecollected at these tongues 40-41, thereby avoiding that such drops arecatapulted towards the passage opening 24.

[0077] In all embodiments the needle hub 6 may be provided of one ormore prolongated parts which at least partially surround the actualprotective means 14, in other words surround the hollow body or housing20. Such needle hub 6 is applied in the embodiment of FIGS. 11 and 12and is shown on itself in FIG. 13. More particularly, this needle hub 6comprises prolongations 48-49-50, respectively in the lateral andpartially in the upper part thereof. This further improvement isintended to prevent the possibility that the operator can disconnect thecannula needle 2 without activating the protective device 1.

[0078] Preferably, the needle 5 is made of AISI 304 steel, and theprotective means 14 and the cannula 3 of acetal resin or polypropyleneor polyethylene.

[0079] According to an important preferred aspect of the invention,which is mentioned in the introductory portion of the description, thescraping means comprise a scraping ring which cooperates with the needle5, said scraping ring for all positions being located inside the housingat a distance from the rear side of the rear wall or end wall of saidhousing. In the previously described embodiments, this is demonstratedby means of the distance D which is indicated in the FIGS. 5, 8 and 10.

[0080] The main advantage of this invention is that it provides aprotective device for a cannula needle to avoid the risk of contact witha patient's body fluids or with drugs wetting the needle, and ofaccidental pricking and wounds, which device is very efficient in manyaspects.

[0081] The device is small and compact and thus easy to use and veryversatile.

[0082] Another advantage is that it provides a protective device that issimple to construct and assemble and is therefore economic.

[0083] A further advantage is that it supplies a needle guaranteeingmaximum protection for the operator during the operation of extractingthe needle from the cannula.

[0084] The present invention is in no way limited to the forms ofembodiment described by way of example and represented in the figures,however such protective device, as well as cannula needle assemblies andneedles provided with such protective device can be realized in variousforms and dimensions without leaving the scope of the invention.

In the claims:
 1. A protective device for a needle, more particularlyfor a catheter introducing needle or so-called cannula needle wherebythis protective device comprises protective means which slidablycooperate with the needle, characterized in that said protective meanscomprise a combination of at least, on the one hand, safety means havingat least one part which, upon retraction of the needle through theprotective means, is placed in front of the needle point and preventsthe re-use of the needle, and, on the other hand, blocking means whichcooperate with the safety means and which, when the protective devicepasses from a non-operative state into an operative state, release saidsafety means from a blocked position into an unblocked position.
 2. Theprotective device according to claim 1, characterized in that the safetymeans and the blocking means are configured in such a manner that, uponretraction of the needle, the safety means, more particularly the partor parts which are placed in front of the needle point, remain at adistance from the needle during the entire retraction thereof.
 3. Theprotective device according to claim 1, characterized in that theblocking means are shiftable in respect to the safety means, such that,by means of a shifting movement of the blocking means, the safety meansare released from a blocked position into an unblocked position, wherebysaid blocking means cooperate with the needle in such a manner that adisplacement and retraction of the needle also causes the above shiftingmovement of the blocking means.
 4. The protective device according toclaim 3, characterized in that the blocking means substantially consistof a sliding ring located around the needle.
 5. The protective deviceaccording to claim 3, characterized in that the needle, at its proximalend, is attached in a needle hub, and in that this needle hub comprisesat least one part which, in the most forward position of the needle,cooperates with the protective means, more particularly is inserted inthe protective means, thereby preventing the blocking means fromcarrying out the above-mentioned shifting movement.
 6. The protectivedevice according to claim 1, characterized in that said part of thesafety means is elastically bendable, such that it is urged into thepath of the needle, respectively said parts are elastically bendable,such that they are urged into the path of the needle, whereby said part,parts, respectively, in their blocked position, are kept at leastsubstantially out of the path of the needle by means of said blockingmeans.
 7. The protective device according to claim 1, characterized inthat said part, parts, respectively, of the safety means consist ofsafety tongues.
 8. The protective device according to claim 7,characterized in that the safety means consist of a pair of safetytongues, which, from opposite sides of the needle, can be brought ontothe path of this needle.
 9. The protective device according to claim 1,characterized in that the protective means and the needle comprisestopping means, acting as abutment means between the protective meansand the needle, which define an end position when retracting the needle.10. The protective device according to claim 9, characterized in thatthe stopping at the needle comprise an annular groove or a ridge orthickening or the like on the outside of the needle and in that thestopping means at the protective means are formed by said blocking meansor by parts cooperating with said blocking means.
 11. The protectivedevice according to claim 1, characterized in that the safety means andthe blocking means are housed in a hollow body, said hollow body beingprovided with passage openings for the needle.
 12. The protective deviceaccording to claim 1, characterized in that the protective means arerealized as an extension piece for a catheter hub, whereby thisextension piece is provided with coupling means for releasably couplingit to said catheter hub.
 13. The protective device according to claim 1,characterized in that it is provided with scraping means to dry theneedle when the device itself passes from the non-operative state to theoperative state.
 14. The protective device according to claim 13,characterized in that the scraping means are formed by and/or fixed atthe blocking means.
 15. The protective device according to claim 13,characterized in that the scraping means comprise a ring or the like,more particularly a plastic O-ring, which is provided around the needle.16. The protective device according to claim 1, characterized in thatthe needle is attached in a needle hub and that said needle hub isprovided with one or more prolongations which at least partiallysurround the protective means.
 17. A protective device for a needle,more particularly for a catheter introducing needle, whereby thisprotective device comprises protective means which slidably cooperatewith the needle, characterized in that said protective means compriseone or more safety tongues which upon retraction of the needle areautomatically positioned in front of the needle point, therebypreventing the needle from being re-used, whereby these tongues upon thecomplete retraction movement of the needle remain at a distance from theneedle.
 18. A protective device for a needle, more particularly for acatheter introducing needle, whereby this protective device comprises ahollow body forming a housing, which body slidably cooperates with theneedle such that the needle can be retracted into a position in whichthe needle point is located in said hollow body, characterized in thatsaid protective device comprises a scraping ring which cooperates withthe needle, whereby this scraping ring is located inside the housing, ata distance from the rear side of the rear wall of said housing.
 19. Aneedle or safety cannula needle assembly, characterized in that it isprovided with a protective device comprising a protective means whichslidably cooperates with the needle, characterized in that saidprotective means comprises a combination of at least, on the one hand,safety means having at least one part which, upon retraction of theneedle through the protective means, is placed in front of the needlepoint and prevents the re-use of the needle, and, on the other hand,blocking means which cooperates with the safety means and which, whenthe protective device passes from a non-operative state into anoperative state, releases said safety means from a blocked position intoan unblocked position.
 20. A catheter introducing needle comprising aprotective device including a protective means for slidably cooperatingwith the needle and the protective means including one or more safetytongues wherein upon retraction of the needle are automaticallypositioned in front of a needle point of the needle for preventing theneedle from being re-used and the tongues upon the complete retractionmovement of the needle remain at a distance from the needle.
 21. Acatheter introducing needle comprising: a protective device including ahollow body forming a housing, the body slidably cooperating with theneedle such that the needle can be retracted into a position in whichthe needle point is located in the hollow body, and a scraping ringwhich cooperates with the needle and is located inside the housing at adistance from the rear side of a rear wall of the housing.